physics worksheet
The PSBB Millennium School Geruhambakkam Chennai XII Physics Worksheet
Electric charges and field
1. 1. An oil drop of 12 excess electrons is held stationary under a constant electric field of 2.55x104 v/m. The density of oil is 1.26 gm/cc. Estimate the radius of the drop.[Ans:1.428x10-6m]
2. Two small spheres each of mass 10-6kg are suspended from a point by silk threads 50 cm long. They are equally charged and repel to a distance of 20cm.Calculate the charge on each.[Ans:3.012x10-9C]
3. Two charges +20µC and -20µC are placed 20cm apart at A and B respectively. Compute the electric field at C 20 cm away from both A and B.[Ans:4.5x106N/C]
4. Calculate the work done in turning a dipole of moment 36x10-6 C m aligned in an electric field of 5X 105 N C-1 through an angle of 180º.[Ans:36J]
5. Two charges +1µC and -1µC are 1 cm apart. Calculate the electric field at a point distant 10 cm from the midpoint (i) on the axial line (ii) on the equatorial line.
6. A uniformly charged conducting sphere of 2.4 m diameter has a surface charge density 80 µC/m2 . Find the charge on the sphere. What is the total electric flux leaving the surface of the sphere?
7. Two point charges +4e and +e are separated by a distance ‘a’. Where should the third point charge be placed for it to be in equilibrium? • 2µC
8. Two equal positive charges each of +2µC and 3m a charge of+3µC are placed as shown. o 4m 3µC
Calculate the magnitude and direction of the 3m force on the +3µC . •2µC
9. How far apart should two protons be placed if the electrostatic force by one on the other is equal to the weight of an electron?
10. Two charges +0.5µC and -0.5µC are 10-3micron apart. Calculate the electric field intensity at a point 20 cm away from their mid point on the equatorial line.
11. An electric dipole is placed at an
Electric charges and field
1. 1. An oil drop of 12 excess electrons is held stationary under a constant electric field of 2.55x104 v/m. The density of oil is 1.26 gm/cc. Estimate the radius of the drop.[Ans:1.428x10-6m]
2. Two small spheres each of mass 10-6kg are suspended from a point by silk threads 50 cm long. They are equally charged and repel to a distance of 20cm.Calculate the charge on each.[Ans:3.012x10-9C]
3. Two charges +20µC and -20µC are placed 20cm apart at A and B respectively. Compute the electric field at C 20 cm away from both A and B.[Ans:4.5x106N/C]
4. Calculate the work done in turning a dipole of moment 36x10-6 C m aligned in an electric field of 5X 105 N C-1 through an angle of 180º.[Ans:36J]
5. Two charges +1µC and -1µC are 1 cm apart. Calculate the electric field at a point distant 10 cm from the midpoint (i) on the axial line (ii) on the equatorial line.
6. A uniformly charged conducting sphere of 2.4 m diameter has a surface charge density 80 µC/m2 . Find the charge on the sphere. What is the total electric flux leaving the surface of the sphere?
7. Two point charges +4e and +e are separated by a distance ‘a’. Where should the third point charge be placed for it to be in equilibrium? • 2µC
8. Two equal positive charges each of +2µC and 3m a charge of+3µC are placed as shown. o 4m 3µC
Calculate the magnitude and direction of the 3m force on the +3µC . •2µC
9. How far apart should two protons be placed if the electrostatic force by one on the other is equal to the weight of an electron?
10. Two charges +0.5µC and -0.5µC are 10-3micron apart. Calculate the electric field intensity at a point 20 cm away from their mid point on the equatorial line.
11. An electric dipole is placed at an